The role of asymptotic functions in network optimization and feasibility studies

Solutions to network optimization problems have greatly benefited from developments in nonlinear analysis, and, in particular, from developments in convex optimization. A key concept that has made convex and nonconvex analysis an important tool in science and engineering is the notion of asymptotic function, which is often hidden in many influential studies on nonlinear analysis and related fields. Therefore, we can also expect that asymptotic functions are deeply connected to many results in the wireless domain, even though they are rarely mentioned in the wireless literature. In this study, we show connections of this type. By doing so, we explain many properties of centralized and distributed solutions to wireless resource allocation problems within a unified framework, and we also generalize and unify existing approaches to feasibility analysis of network designs. In particular, we show sufficient and necessary conditions for mappings widely used in wireless communication problems (more precisely, the class of standard interference mappings) to have a fixed point. Furthermore, we derive fundamental bounds on the utility and the energy efficiency that can be achieved by solving a large family of max-min utility optimization problems in wireless networks.Comment: GlobalSIP 2017 (to appear

Bifurcations and Averages in the Homoclinic Chaos of a Laser with a Saturable Absorber

The dynamical bifurcations of a laser with a saturable absorber were calculated, with the 3-2 level model, as function of the gain parameter. The average power of the laser is shown to have specific behavior at bifurcations. The succession of periodic-chaotic windows, known to occur in the homoclinic chaos, was studied numerically. A critical exponent of 1/2 is found on the tangent bifurcations from chaotic into periodic pulsations.Comment: 6 or 7 pages, 3 figures, publishe

Subwavelength position sensing using nonlinear feedback and wave chaos

We demonstrate a position-sensing technique that relies on the inherent sensitivity of chaos, where we illuminate a subwavelength object with a complex structured radio-frequency field generated using wave chaos and a nonlinear feedback loop. We operate the system in a quasi-periodic state and analyze changes in the frequency content of the scalar voltage signal in the feedback loop. This allows us to extract the object's position with a one-dimensional resolution of ~\lambda/10,000 and a two-dimensional resolution of ~\lambda/300, where \lambda\ is the shortest wavelength of the illuminating source.Comment: 4 pages, 4 figure

Instruções práticas para o cultivo do milho nas várzeas do Amapá.

Preparo do solo; Semeadura; Cultivar; Tratos culturais; Pragas de importância economica; Controle de pragas; Controle de doenças; Rotação de culturas; Colheita; Secagem; Beneficiamento; Armazenamento; Comercialização; Coeficientes tecnicos.bitstream/item/96059/1/CPAF-AP-1990-Cultivo-Milho.pd

Incidência de doenças em linhagens de arroz de terras altas.

Vários fatores podem afetar a lavoura de arroz, entre eles, as doenças são motivo de grande preocupação para os produtores, pois diminuem a produtividade e afetam a qualidade de grãos. O clima quente e úmido favorece o aumento da severidade da maioria das enfermidades. Atualmente, as doenças do arroz, estão sendo manejadas através da associação do controle químico ao uso de cultivares resistentes. A prevalência e a severidade das doenças dependem da presença de patógeno virulento, de ambiente favorável à incidência e da suscetibilidade da cultivar.bitstream/item/97081/1/CPAF-AP-2002-Doencas-arroz.pd

Teste de cultivares de mandioca no Amapá.

A mandioca é uma das principais culturas de subsitência da Amazônia brasileira. É cultivada por pequenos agricultores, constituindo-se em alimento básico da maioria da população, especialmente a de baixa renda...bitstream/item/96766/1/CPAF-AP-2002-Teste-mandioca.pd

Linhagens de arroz de terras altas do Amapá.

No Amapá o cultivo do arroz tem a finalidade de subsistência com predominância total em terras altas. A indisponibilidade de cultivares com qualidades superiores e não utilização de fertilizantes e corretivos de solo, são alguns dos fatores que afetam o desempenho da cultura. Este trabalho teve a finalidade de avaliar o comportamento de vinte e seis linhagens/cultivares de arroz no ecossistema de terras altas do Amapá.bitstream/item/97073/1/CPAF-AP-2002-Arroz-terras.pd